1. Field of the Invention
The invention relates generally to the field of structural dunnage devices, adapted to fill voids within a truck, van, or seagoing container so that goods will not shift or topple into these voids, during transit. More particularly, the invention pertains to a dunnage device for use with individual pallet units, or skids, which have been isolated, or "singled out" from the remaining units, to redistribute the entire load throughout the transport container.
2. Description of the Prior Art
Generally representative of a prior art structural dunnage device is the cellular void filler shown in U.S. Pat. No. 4,372,717, issued to Sewell, et al. Such a void filler is typically used between two spaced pallet units, transversely arranged in an elongated transport van, so that the combination of the two units and the void filler spans the width of the van. The void filler of Sewell et al. is further designed to be suspended, or hung, from the top, opposing edges of the units, and to extend downwardly between their opposing faces, substantially to the floor. In this application, the dunnage device prevents side-to-side, or lateral shifting of the units during transit.
Unwanted front to rear displacement of the pallet units is prevented by filling almost the entire length of the van with units, and then placing a rigid bulkhead, constructed from faced corrugated paperboard, within the remaining tailgate void. However, as modern transport vans have become exceptionally long, shippers are occasionally unable to fill the entire van or trailer with goods, for each shipment. This results in smaller, partial loads being sent, and unavoidably increases the number of dunnage devices required to fill the nonutilized space.
It should also be noted that a partial load cannot be concentrated either in the forward, or in the rearward portion of the trailer, for safety reasons. The partial load must be properly distributed between the fore and aft axles of the trailer, by appropriately intermixing pallet units and dunnage devices throughout the length of the van, until the van is filled.
A technique has been developed in the trade called "singling out", for effectively stretching the longitudinal extent of the pallet units included in the partial load. Instead of arranging pallet units in transversely oriented pairs spaced apart by a dunnage device, a single pallet unit is alternatively positioned along the van's center line, and an individual dunnage device is placed within each void between the pallet unit and a respective sidewall of the van. This technique allows the use of lighter duty dunnage devices to resist the moderate lateral forces, while the end-to-end abutting pallet units and bulkheads resist the more powerful fore and aft forces typically encountered during transport.
The transverse dimension, or thickness of the dunnage device typically required to satisfy the pallet unit-to-sidewall void is approximately in the range of 20" to 30". Owing to the substantial weight of such a dunnage device, it must, of necessity, be supported both by the pallet unit and by some means of attachment to the sidewall of the van or container, to avoid sagging or dropping completely. However, efforts to support such a heavy dunnage device by mechanical attachment to the container's sidewall have heretofore been unsuccessful. Many of the vans, trailers, or containers use either fiberglass or relatively thin plywood for sidewall material. Fiberglass is too difficult to nail into, and thin plywood is not strong enough to withstand the repeated breakage and stress.
It is a primary object of the present invention to eliminate this reliance on the two previously required, but unsuccessful, sidewall attachments, and to provide a unitary dunnage device which prevents transit creep of a single pallet unit in either lateral direction. It is also an object of the present invention to provide a dunnage device for single pallet units which can be installed more quickly and easily than prior art devices.